iomap,xfs: Convert ->discard_page to ->discard_folio

XFS has the only implementation of ->discard_page today, so convert it
to use folios in the same patch as converting the API.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

Author: Matthew Wilcox (Oracle)

fs/iomap/buffered-io.c

@@ -1360,8 +1360,8 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc,
 		 * won't be affected by I/O completion and we must unlock it
 		 * now.
 		 */
-		if (wpc->ops->discard_page)
-			wpc->ops->discard_page(page, file_offset);
+		if (wpc->ops->discard_folio)
+			wpc->ops->discard_folio(folio, file_offset);
 		if (!count) {
 			ClearPageUptodate(page);
 			unlock_page(page);

fs/xfs/xfs_aops.c

@@ -437,37 +437,37 @@ xfs_prepare_ioend(
  * see a ENOSPC in writeback).
  */
 static void
-xfs_discard_page(
-	struct page		*page,
-	loff_t			fileoff)
+xfs_discard_folio(
+	struct folio		*folio,
+	loff_t			pos)
 {
-	struct inode		*inode = page->mapping->host;
+	struct inode		*inode = folio->mapping->host;
 	struct xfs_inode	*ip = XFS_I(inode);
 	struct xfs_mount	*mp = ip->i_mount;
-	unsigned int		pageoff = offset_in_page(fileoff);
-	xfs_fileoff_t		start_fsb = XFS_B_TO_FSBT(mp, fileoff);
-	xfs_fileoff_t		pageoff_fsb = XFS_B_TO_FSBT(mp, pageoff);
+	size_t			offset = offset_in_folio(folio, pos);
+	xfs_fileoff_t		start_fsb = XFS_B_TO_FSBT(mp, pos);
+	xfs_fileoff_t		pageoff_fsb = XFS_B_TO_FSBT(mp, offset);
 	int			error;
 
 	if (xfs_is_shutdown(mp))
 		goto out_invalidate;
 
 	xfs_alert_ratelimited(mp,
-		"page discard on page "PTR_FMT", inode 0x%llx, offset %llu.",
-			page, ip->i_ino, fileoff);
+		"page discard on page "PTR_FMT", inode 0x%llx, pos %llu.",
+			folio, ip->i_ino, pos);
 
 	error = xfs_bmap_punch_delalloc_range(ip, start_fsb,
-			i_blocks_per_page(inode, page) - pageoff_fsb);
+			i_blocks_per_folio(inode, folio) - pageoff_fsb);
 	if (error && !xfs_is_shutdown(mp))
 		xfs_alert(mp, "page discard unable to remove delalloc mapping.");
 out_invalidate:
-	iomap_invalidatepage(page, pageoff, PAGE_SIZE - pageoff);
+	iomap_invalidate_folio(folio, offset, folio_size(folio) - offset);
 }
 
 static const struct iomap_writeback_ops xfs_writeback_ops = {
 	.map_blocks		= xfs_map_blocks,
 	.prepare_ioend		= xfs_prepare_ioend,
-	.discard_page		= xfs_discard_page,
+	.discard_folio		= xfs_discard_folio,
 };
 
 STATIC int

include/linux/iomap.h

@@ -285,7 +285,7 @@ struct iomap_writeback_ops {
 	 * Optional, allows the file system to discard state on a page where
 	 * we failed to submit any I/O.
 	 */
-	void (*discard_page)(struct page *page, loff_t fileoff);
+	void (*discard_folio)(struct folio *folio, loff_t pos);
 };
 
 struct iomap_writepage_ctx {